1. Field of the Invention
The invention is directed to a T-link of two profile bars, with a link comprising two elongate clamping jaws which can be tightened transversely by a fixing element and can be locked in position, closing like tongs, in undercut casing grooves of a second profile bar, and which engage endwise in a cavity of a first profile bar and can be clamped onto cylindrically parallel inner webs of the first profile bar that are arranged between said clamping jaws.
2. Description of Prior Art
A T-link having the aforesaid features is known from GB A 1,557,693. The first profile bar, configured as a rectangular tube whose narrow walls are provided with the mutually assigned inner webs, is connected to the second, polygonally implemented profile bar. One clamping jaw is arranged between each pair of inner webs and the wide wall of the tube and protrudes from the first profile bar, the fixing element being disposed inside the tube and actuated through a hole in the first profile bar. If the clamping jaws are tightened by means of the fixing element, the clamping jaws bear against and pinch the webs in the vicinity of the fixing element. At the same time, the end edges of the clamping jaws spread apart and grip, by a hook-shaped portion, the inner walls of the first profile bar, enabling the jaw portions of the clamping jaws protruding from the first profile bar to be locked in position, tong-like, in the undercut casing grooves of the second profile bar. Each clamping jaw is therefore braced at three locations, i.e., on both sides of the fixing element and at its edges inside the tube. However, the clamping locations, particularly those in the first profile bar, are small in area, and the T-link therefore seems to merit improvement in this respect. It is limited to the use of a rectangular first profile bar.
The object of the invention is, therefore, to improve a T-link having the features cited in the introduction hereto in such a way that increased connection strength is achieved, particularly with the use of profile bars of arbitrary cross section.
This object is accomplished in that the first profile bar comprises more than two inner webs evenly distributed about its inner circumference, in that tightened clamping jaws exclusively clamp inner webs with longitudinally linear and/or planar contact, and in that the clamping jaws engage by each of their longitudinal edges in a respective clearance provided between the clamped inner web and the inner web adjacent thereto.
It is of significance for the invention, first, that the first profile bar has more than two inner webs evenly distributed about its inner circumference. Such multiple inner webs can be distributed as needed, especially in the case of profile bars of arbitrary cross section. In such arrangements, the clamping jaws can be positioned at locations where they are of pre-eminent importance with regard to connection strength. It is of significance, further, that tightened clamping jaws exclusively clamp inner webs. There is no need for contact with the inner walls of the first profile bar. The inner contour of the first profile bar, and thus its outer contour as well, are of no importance with regard to the connection strength of the T-link. The requisite connection strength is instead achieved by the fact that the clamping is effected with longitudinally linear and/or planar contact. This consequently produces long and/or large-area clamping regions that make it possible to obtain an adequate force fit between the clamping jaws and the inner webs. The large contact areas of the jaws on the inner webs prevent stress peaks that might deform the inner webs or the first profile bar. At the same time, the inner webs make it possible for the link to be inserted to its full clamping length into the first profile bar and thus for its position to be adjusted as need be. It is of significance, further, that the clamping jaws engage by each of their longitudinal edges in a clearance-provided between the clamped inner web and the inner web adjacent thereto. The clamping jaws are therefore realized with the largest possible cross section. Their longitudinal edges can be disposed near the inner wall of the first profile bar, thereby permitting a large jaw cross section. In this way, clamping forces acting on the inner webs are not adversely affected by instabilities of the clamping jaws caused by unsatisfactory cross-section design.
An advantageous T-link is realized so that the inner webs are distributed about the inner circumference of the first profile web at intervals of forty-five angular degrees. Thus, there are three different options for arranging the clamping jaws in the first profile bar, and the second profile bar can thus be arranged in three different angular positions with respect to the first. This is of significance in particular when the profile bars have rectangular or non-round cross sections that must be used to capacity in order to impart particular loading and/or shape characteristics to a structure made from profile bars. To promote the secure retention of the link in the first profile bar, the inner webs of the first profile bar are arranged diametrically opposite each other and evenly distributed about the circumference of the inner wall of the first profile bar. In this way, the clamping jaws of the first link embrace two inner webs at a time, thereby achieving good retention. Tolerance in obtaining a firm seat for the clamping jaws is provided in that the inner webs can be clamped more forcefully than necessary without causing problems, and can even undergo some plastic deformation without any adverse effect on the stability and functional efficiency of the first profile bar or the link. This is especially advantageous with regard to nonprofessional users, since the proper locking force is not always applied. If the inner webs are evenly distributed about the circumference of the inner wall of the first profile bar, the link can be applied in different positions of the first profile bar, thereby permitting greater flexibility and easy assembly.
The T-link can be realized so that each of the inner webs is aligned with one of the casing grooves. This embodiment is especially advantageous if the first profile bar is provided outwardly with casing grooves over at least some portions of its circumference. This improves the bending rigidity of the first profile bar and further stiffens its inner wall, especially in the region of a casing groove.
An advantageous improvement of the T-link is distinguished by the fact that each inner web has a thick base and, extending radially therefrom, a thinner clamping strip that can be clamped between the clamping jaws. The thick base is designed to improve stability: not only the stability of the first profile bar, but also, and more important, the stability of the inner webs, to the extent that they are realized to extend comparatively far into the interior of the first profile bar. The thinner clamping strips might cause instabilities if, for structural reasons, the clamping jaws did not extend near enough to the inner walls of the profile bar. The stability of the thin clamping strips would then be inadequate near the inner wall of the first profile rod. This is particularly a concern when a structural system is designed to employ first profile bars of different cross sections that are to be used with same-sized clamping jaws. It is then necessary to use wider inner webs, i.e., inner webs that project farther radially inward.
In accordance with the foregoing, the T-link can be improved in such a way that, the width of the clamping jaws being given, the extension of the thick bases of the inner webs in the radial direction is determined by the distance between two diagonally opposite clamping strips. Such embodiments find application particularly in connection with the use of first profile bars in which oppositely disposed inner webs are of unequal width, for example because the cross sections comprising inner webs are configured asymmetrically or in another special manner.
It can be advantageous to realize the T-link so that when the profile bars are in a final a assembled position, the fixing element of the link can be actuated through a clearance between one end of the first and a casing surface of the second profile bar. Actuating the fixing element of the link through a clearance between one end of the first profile bar and a surface of the second profile bar when the profile bars are in a final assembled position makes it possible to link a large variety of profile bars of different shapes that need not be coordinated with one other. There is no need for either the first or the second profile bar to have fixed positions for holes or crosscuts, which would make it difficult for a nonprofessional user to dimension the profile bars. The link between the profile bars is therefore one that can readily be assembled and that effectively withstands longitudinal and transverse loads. It is nearly impossible for the link to be lost or to slip down into the first profile bar, because the fixing element, in addition to serving the purpose of clamping, simultaneously acts as a coupling while the structure is being assembled or moved.
Particularly in the foregoing embodiment, the end of the first profile bar can be realized without a retaining hole or an actuating hole. Thus, there is no need either for a retaining hole in which a portion of the link must be braced so as not to be pulled longitudinally out of the first profile bar, or for an actuating hole for actuating the fixing element. Such embodiments make it possible for profile bars to be cut to length at any desired location. This makes for minimal technical expenditure and consumption of time. For example, it is not necessary to maintain any preset spacing between the link and the first profile bar, and the profile bars can also, if necessary, be positioned and secured within a range of spacings from each other that is defined by the longitudinal extension of the fixing element. Subsequent adjustments can still be made, despite the presence of a clamping T-link. The relative positions of the two profile bars can be altered without disassembling the link or the profile bars. Thus, the T-link can be used without problems by one person, who, moreover, need not possess any specialized technical knowledge. The T-link can therefore be used satisfactorily by lay people and can readily be sold to anyone.
To improve protection against loss and to achieve greater rigidity and more compact construction plus higher stability, the link consists of no more than two clamping jaws realized as separate parts, adjustably connected by the fixing element. Few manipulations are necessary to fit this minimal number of parts together to form the link and attach them to the second profile bar. The fixing element holds the clamping jaws together while they are being mounted in place, and in the mounted state exerts a locking force thereon that presses the two separate parts of the link together or apart, thereby securing them to the first and second profile bars.
If a fixing element realized as a screw is inclined with respect to the longitudinal direction of the first profile bar and/or the end of the first profile bar is disposed at a distance from the second profile bar, a tool can readily be deployed between the two profile bars. The inclined screw inserted in the inclined screw insertion channel can be manipulated on the link both at its head end and at its foot end, provided that there is sufficient spacing between the profile bars, especially in the case of the second variant.
If the screw serving as the fixing element is tilted with its head toward the second profile bar, the fixing element can be actuated through the clearance between the profile bars even when the spacing between the two profile bars is very small, for example due to the meeting of a straight with a curved profile bar. Whether or not the head of the screw can be reached depends solely on the diameter of the tool. Depending on the implementation of the screw head, the spacing between the two profile bars can be reduced further if a very narrow tool is selected. The force that must be applied is not very great, even with thick profile bars, because of the direct conversion of the force.
It is advantageous if the link has, for the fixing element, one hole extending perpendicularly to the clamping jaws and another hole extending obliquely thereto. In this way, the link can be used both for screws that are inserted straight and those that are inserted obliquely. This makes it a universally applicable type of link, thus lowering production costs; it is not necessary for the user to purchase different types of links, even if he plans to interconnect an extremely wide variety of profile bars, especially hollow profile bars.
So that the link can be secured perpendicularly in the same casing grooves of the second profile bar in different angular positions with respect to the longitudinal axis of the profile bar, the link comprises slots in the clamping jaws for the insertion of the fixing element and/or the tong legs of the link can be clamped to the second profile bar in different angular adjustments of the link by means of ball-shaped leg ends that are inserted into the undercuts of the casing grooves. In this way it is possible to make angular adjustments (oblique angle xc2x1xcex1) of the first profile bar to either side of the normal position (xcex1=0). The presence of a slot in one clamping jaw ensures that the strength and quality of the connection will be the same as with vertical insertion.
To increase stability, it is advantageous that the clamping jaws be in a reciprocal positive engagement that prevents relative transverse and/or parallel movement. Such reciprocal positive engagement substantially increases stability with only a small increase in materials-related and production expenditure. The positive engagement is brought about simply by fitting the clamping jaws of the link together, and can be released in the same simple manner if the link is to be shifted or used for another connection.
Especially for the angular arrangement of the link relative to the second profile bar, it is advantageous if a saw-tooth-shaped reciprocal-positive-engagement arrangement is present on the inner surfaces of the clamping jaws and/or if ribs and/or dogs are provided that mate with slots in the other clamping jaw. Different form-fitting connection sites can be created in this manner. Providing a fine saw-tooth or the like reliably ensures angular adjustment of the link that encompasses nearly all the oblique angles xcex1. Ribs and/or dogs on the clamping jaws can be realized as more or less solid and are therefore suited in particular for solid implementations of the clamping jaws.
It is advantageous if the link has dimensions such that plural links with first profile bars connected thereto can be mounted next to one another at the same height on the second profile bar. This can advantageously be accomplished by having one tong leg of a clamping jaw of a link occupy no more than one half of a cross section of a casing groove of the second profile bar, into whose other half a tong leg of another link can be fitted.
This can be accomplished, in particular, in that the link and the end of the first profile bar does project beyond the median planes of two casing grooves which are occupied by clamping jaws and both of which extend through the longitudinal axis of the second profile bar. If no portion of the link projects beyond the aforesaid median planes, a second link can easily be mounted at the same height on a second profile bar. First profile bars of various contours can be fastened to the second profile bar by means of the links. The sole condition is that the end of the profile bar not project beyond the aforesaid median planes of the link concerned or adjacent links.
It is preferable that the tong legs be form-fittingly adapted to an undercut of a casing groove of the second profile bar. The tong legs thereby engage in the undercuts. The connection between the tong legs and the second profile bar are connected to each other against accidental detachment more effectively, that is, with a stronger form-fit. When the clamping jaws are tightened by means of the fixing element, a form fit is immediately produced between the tong legs and the undercut. This facilitates subsequent adjustment of the relative positions of the profile bars by displacement in the region of the form fit without it being necessary to take the connection completely apart for this purpose.
It is advantageous for the T-link if, when the tong legs are locked in position on the second profile bar, the clamping jaws have a spacing between them that permits linear and/or planar clamping of the inner webs. The clamping jaws are thus prevented from contacting each other in the vicinity of the second profile bar, which would hinder the proper clamping of the tong legs to the second profile bar and the force-fit of the clamping jaws in the inner webs.
It is especially advantageous if the two profile bars have both inner webs and casing grooves. Links can thus be inserted in both profile bars or mounted on them from the outside. This permits a large variety of connections, and the user need not pay attention to the type of connection for which the profile bar is actually intended. At the same time, the profile bar can be cut to length as needed and satisfies the requirements in terms of stability and use of the link at arbitrary locations. In addition, production of the profile bars is simplified if there is only one kind of bar.
The fixing element is arranged in an especially user-friendly manner and is especially easy to reach when the first profile bar is spaced apart from the second profile bar, thereby leaving the fixing element exposed radially. The fixing element thus can be reached and actuated easily with various tools. Again, there are no problems with respect to the stability of the link, owing to its large contact area with the inner webs or the inner circumference of the first profile bar.
Engagement of the tool in the fixing element is facilitated if the clearance leaving the fixing element exposed is formed between a cut-off end of the first profile bar and a polygonal or curved casing of the second profile bar. If the end of the first profile bar and such a polygonal or curved casing of the second profile bar abut each other in the final assembled position, the link is imparted a firmer hold by the additional support. Furthermore, the fixing element can easily be reached by the tool through the clearance formed as a result of the slope of the casing surface of the second profile bar in the case of a polygonal or curved shape. The slope produced by the polygonal or round shape can be realized so that it is adapted to the angular position of the inserted tool, thus providing guidance for the tool.
To protect the connection point, it is advantageous that the link and the end of the first profile bar be covered by a cap disposed between the first and second profile bars. This prevents the ingress of dirt or moisture into locations on the first profile bar that have been left uncovered by the link and keeps any objects that may brush past the link from catching on its points or edges. Another purpose of this cap is to provide a visually pleasing implementation for the transition from the first to the second profile bar.
To render the link easy to implement and inexpensive to manufacture, it is constructed in one piece, of a formed metal sheet that lends it rigidity, with two clamping jaws, each of which comprises a tong leg. The sheet-metal construction reduces the weight of the link while providing a reliable fit due to the one-piece construction. In addition, sheet metal is easy to shape, which is especially important in the case of the tong legs in order to provide an exact form-fit and secure retention on the outer casing grooves and so that angular adjustments can be made precisely.
An advantageous, sturdy implementation of the link consists in realizing the clamping jaws as solid. Such solid construction ensures that the link will not deform, even when vigorously tightened. In addition, it is especially easy in this case to add formed-on elements that prevent relative parallel movement by being in reciprocal positive engagement.
A further substantial improvement of the T-link is achieved by giving the elongate clamping jaws opposite cambers from end to end. Owing to their camber, the clamping jaws are spaced apart from each other in the region of the fixing element. Actuating the fixing element causes this spacing to be eliminated and the clamping jaws to contact each other, especially in the region of the inner webs, in a force-fitting manner, specifically planarly or linearly in the longitudinal direction of the clamping webs. This excludes the possibility of the clamping jaws resting on the inner webs only at points or for short distances. This is true in particular when the fixing element acts with a predetermined force on the two clamping jaws, which are clamped by means of tong legs to the second profile bar and simultaneously clamp the inner webs of the first profile bar. When a screw is used as the fixing element, such a force exerted on the clamping jaws is predetermined by the fact that the screw is tightened to a set tightening torque.
An improvement of the T-link can provide that the clamping jaws are provided at their ends with slots which, when the clamping jaws are tightened, constitute circumferential portions of a bore and/or a threaded bore. The bore or threaded bore can be used for mounting or fastening purposes in the region of the T-link. In addition, such bores make it possible to use the link for other purposes than its designated one of interconnecting two profile bars.
Use of the link is facilitated if the clamping jaws are clasped together in pairs by spring clips. This is the case, in particular, when the two clamping jaws are not yet joined together in a captive manner by a fixing element, or when a fixing element that is already present does not, or does not yet, hold the clamping jaws of the link captive.
A further advantageous embodiment of the T-link is distinguished by the fact that the clamping jaws are provided on both sides with oblique faces to center them on the inner webs. Said oblique faces serve the purpose of automatically positioning the clamping jaws on the inner webs, especially during the securing of the clamping jaws. They prevent the clamping jaws from being seated too far onto one inner web and failing to grip the other inner web adequately.
Realizing the clamping jaws of the link as ball-shaped at the insertion end makes it possible to adjust the first profile bar to almost any desired angular position between 0 and 45xc2x0, measured between a vertical to the longitudinal axis of the second profile bar and the longitudinal axis of the first profile bar, and limited only by the end of the first profile bar and the tong ends of the link. The clamping jaws are then locked in place, as described hereinabove, by squeezing them together or forcing them apart inside the first profile bar.
An especially light and multi-purpose structure is obtained if both profile bars are hollow profile sections. The profile bars can be provided with inner webs and casing grooves over their entire length. In this way, profile bars cut to any desired length will always afford a secure hold for the link applied to them, because the webs and grooves are present throughout. A structural unit is then a bar of the desired total length that can be divided into smaller bars, together with the desired number of identically realized links.
The first profile bar is held securely on the second profile bar, even under high transverse loads, if the jaws are locked in position on the second profile bar skipping one casing groove. This type of arrangement provides a sufficiently broad base for xe2x80x9cwobble-freexe2x80x9d support of the link. If the casing of the second profile bar is round, the forces exerted on the casing surface by the tong-like ends of the link are directed almost in a tangent to the casing surface. Thus, the forces that are generated with the proposed arrangement of the link do not deform the second profile bar, but instead merely act parallel to its casing surface. Much greater forces can be withstood in this manner than when the force components are predominantly perpendicular to the casing surface. The proposed fastening arrangement therefore ensures retention by the link that is more secure and at the same time places minimal stress on the profile bars.
The T-link can be realized in such a way that profile bars of, if necessary, different cross sections comprise casing grooves having the same pitch and/or so that the inner webs of both profile bars are arranged in the same assignment to one another or at the pitch of the casing grooves. In particular, casing grooves of the same pitch on both profile bars furnish an attractive outward appearance for the structure as a whole and also improve the feasibility of different structures. If the inner webs of both profile bars are used in the same assignment to one another, this promotes the desired uniform appearance of the structure. A similar effect can also be achieved or enhanced by having the inner webs of both profile bars be arranged in the same assignment to the pitch of the casing grooves.
Structures made from profile bars can pose the requirement that profile bars have different moments of resistance or resistance loads in different planes. This is true, for example, of profile bars with oblong cross sections. To this end, the T-link can be improved such that profile bars of oblong cross section have at least one subdividing transverse wall occupied by inner webs whose distance from aligned inner webs of the profile bars and/or additional transverse walls is adapted to the width of the clamping jaws. The inner webs of the transverse wall can also be used to connect the associated profile bar to another profile bar by clamping. For this purpose, the link used or its clamping jaws employ, in the described manner, mutually opposite inner webs of a transverse wall or an inner wall of a profile bar or another, additional transverse wall.
An embodiment of a profile bar that is especially resistant to bending is refined in a T-link, in that between two transverse walls of a profile bar of oblong cross section there is space to arrange a link whose clamping jaws can be clamped onto inner webs of two wall segments of the profile bar that connect the transverse walls to each other. This enables a link to be arranged centrally.